Individual Pattern Response to CO₂-Induced Acidification Stress in Haliotis rufescens Suggests Stage-Specific Acclimatization during Its Early Life History

Round 1

Reviewer 1 Report

The paper submitted by Goméz-Reyes et al. describes and analyses a considerable amount of data. The experiments are presented in detail, evidencing thorough planning and implementation of a good experimental design. The authors dedicated an extensive amount of work the manuscript. However my opinion is that the amount of detail expressed in the manuscript is in excess, making the Material & Methods section overly extensive. The Figure captions are also extensive, I suggest streamlining the article. Possibly locating some of the information to Supplementary/Appendix.

Overall the MS is well written, well designed and findings discussed in a convincing manner. I believe the paper fits well Sustainability, presenting  interesting findings. I suggest accepting the MS after streamlining the text, better explaining few experimental details, few English editing tips.

Specific comment are given below:

Lines 65-68: please provide a time span (hrs/days/months) regarding what is considered "short term" or "long term" acidification.

Line 74: I suggest restructuring the sentence. What do the authors mean by "Prevalence"? Is prevalence a type of "body compensatory mechanism" as the authors suggest? This sentence is misleading, it is not clear what the authors mean by "prevalence" nor "body compensatory mechanisms". Please clarify.

Line 76: Please rephrase "little population structure" do you mean weak population structure? What do you mean?

Line 79: "in the red abalone species"?  Please correct the sentence

line 80: stressors like acidification.

87: please correct to: conduct an acidification experiment to assess the prevalence of long-term...

88: "remarkable"?

99: To achieve control of pH in seawater...

Figure 1 caption: Either transfer the Figure entirely to Supplementary/Annexes; or streamline the caption text; or transfer the information to the M&M section in written form; or separate image A and B to form separate Figures (1/2) As it is, the caption is to extensive and makes it hard for the reader to follow the design.

Line 161: Why state the exact number of eggs? Were the eggs counted to the individual? Could be presented in a simpler form e.g 1.7x10⁶

^{Table I Caption: Again the caption is very extensive. Is it possible to streamline, or provide a figure showing the ontogenic features at each developmental stage?}

^{Line 332: calculated for the early life history. Please correct}

^{341: Do you mean:  resulted in significant differences (...) regarding hatching success between low pH challenge and Control. Please correct accordingly.}

^{408: why is the pH challenge 7.6 and 7.4 here, as opposed to pH 7.8 7.6 previously described in the M&M section?Please clarify accordingly}

^{Lines 489/537/553/567: Is acclimatisation the correct word in this context?}

^{539: DO the authors mean "burden" instead of "Yield"? Please correct}

^{544: recruitment into/towards benthic life style. Please correct "give birth to"}

^{594: Please rephrase: "environmental variability genetic signatures". What does this mean?}

^{603: Please confer the meaning of "sentinel species" and revise accordingly.}

^{621: Which critical thresholds were identified by the study?Please confer, or explain in the MS accordingly}

The English is average/good. A few editing needs were detected and shared with the authors for correction.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

I don't understand why the authors decided to plot most of the data in the supplemental material. The results are very interesting and can make contributions in the field. 

I didn't understand exactly from mdpi policy if supplementary materials will be accessible after the article is published. However, I kindly ask the authors to insert the graphs from the additional material in the paper. These are important enough results to be included in the paper and are already discussed.

The same goes for appendix A, that little paragraph can easily be inserted into the text, to the methodology. I don't consider it to be an appendix.

Moreover, I kindly ask the authors to better motivate the study in the introduction part.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

In the present study, red abalone embryos were reared under long-term CO2-induced acidification (pH 7.8 and 7.6) and evaluated. Impairment prevalence was assessed during their larval stages, considering developmental success, growth, and calcification. The topic is important and interesting to the readers and appropriate for the scope of the Sustainability journal. The authors have contributed to presenting the tolerance limits and pathways of the stress response, providing valuable insights for exploring the vulnerability of H. rufescens to ocean acidification. Therefore the paper has a novelty. Moreover, the introduction provides sufficient background and references.   The research design and the methods are well described. The results are clearly presented. Overall, the paper is well written.

Author Response

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Reviewer 4 Report

This is certainly an interesting manuscript which provides data on an important commercial taxon and its vulnerability to the increasingly serious threat of environmental change. It focuses on the early life stages which have been shown in many taxa to be especially vulnerable. I cannot claim to be particularly expert in the experimental design and so my comments are limited to the parts of the text which I can sensibly approach.

The abstract pronounces that this species is pivotal to worldwide aquaculture. Whilst I acknowledge its importance regionally, worldwide seems a bit exaggerated for something which is limited geographically.

Taxonomy

Haliotis rufescens  needs to be in italics throughout – the use of brackets in Line 47 is perhaps unhelpful and there should not be a comma between the name and Swainson. Better to write it properly, without the brackets as Haliotis rufescens  Swainson, 1822

It might be good to refer to this as belonging to the Vetigastropoda

Shell details

Line 283 I do not think I would refer to this as shell structure – really they are just images of the surfaces

I find Figure 6 interesting but it could be improved a lot. The extraneous data line could be removed and just a scale bar added. It is not at all clear to me exactly what is going on. It would be better if the detailed surface views where all the same magnification. I find it difficult to see (d) and (e) as significantly different – (e) looks very similar just higher mag! Similarly I don’t see the evidence that (f) is more corroded – actually it may look less?  What are those strange features on the surface – are they typical of Haliotis ? The text refers to it as granular – but granular what?  Are they corroded prisms? I am also not at all clear what areas these views are looking at – they need showing on the low mag picture – I think it is probably from the protoconch but that is unclear and the arrow head is rather vague (use a box to make it clear. In fact they seem to point to different places on the protoconch. The protoconch appears to have an external layer that is sometimes missing – and the missing element appears to be fractured off? Is this the microfracture referred to in Line 467.  I suppose my nagging worry is that some of this is artefactual. It would certainly benefit from higher magnification micrographs and a clear idea of what the material is, as well as a clear statement of the number of individual studied in this way.

 I am also a bit baffled about the discussion of aragonite – are we just talking about the protoconch which I guess is aragonitic but surely the outer layer of the peristomal shell is calcitic on the outside?

Line 419 – I am not sure that ‘decrement’ is a word often used (I had to look it up)

I have no need or wish to remain anonymous.

Line 447 - µ incorrectly rendered

Liz Harper

Not at all bad - just a bit of editing needed. Some strange words, like decrement, used

Author Response

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Author Response File: Author Response.pdf